1. Field of the Invention
This invention relates generally to power supplies and more particularly, to power supplies having a regulated output.
2. Description of Prior Art
Conventional charger utilizing USB port adopts linear regulator for its charging technology. Conventional linear regulator provides stable output voltage. The output voltage is lower than the unregulated input voltage. The linear regulators offer a number of advantages, one of which is good regulation with low cost. However, they also suffer from several drawbacks, the primary one of which is inefficiency. Power that is not consumed by the load is dissipated as heat. Situations that combine high heat and insufficient heat dissipation may result in a rapid and extreme rise in body temperature. It may cause serious system malfunctioning and reliability issues. Moreover, the charging current is confined by the input end of the USB port. Therefore, it takes long time to fully charge the battery.